For years, China has proclaimed its ambition to boost its colleges and universities into the ranks of the world's finest. Lately it has also been signaling another objective - purging campuses of liberal ideas. NPR's Anthony Kuhn reports from Beijing that the trend has implications beyond China's borders.

ANTHONY KUHN, BYLINE: Shi Jiepeng was fired from his job at Beijing Normal University in late July. I met him at a cafe outside the university where he taught classical Chinese. He didn't get in trouble for anything he said in the classroom. Apparently it was a column he wrote for a newspaper and his social media postings that did it. He said the school accused him, among other things, of expressing views that were outside the mainstream of society.

SHI JIEPENG: (Through interpreter) Sure, my views are a bit different from the mainstream or from official views. But an open society should be able to tolerate them.

KUHN: Online, Shi criticized Chairman Mao, the leader of China's Communist Revolution. But as he points out, the party itself admits that Mao made mistakes, so he feels this shouldn't have gotten him fired. Another former ruler who Shi criticized is Emperor Wu of the Han dynasty, who ruled China more than 2,000 years ago. Wu conquered foreign lands and built a strong state but, Shi argues, at the cost of too many lives.

SHI: (Through interpreter) That's because I believe the welfare of the individual is more important than any ruler's political or military achievements.

KUHN: Shi says people who disagreed with his views reported him to Communist anticorruption watchdogs who've been combing university campuses for subversives. After being fired, Shi Jiepeng turned for advice to a prominent liberal historian named Zhang Ming, who recently retired from the prestigious People's University in Beijing. Speaking by phone, Zhang told me that he thought firing Shi Jiepeng was unprecedented and it appeared to be entirely Beijing Normal University's fault.

ZHANG MING: (Through interpreter) No doubt politics are veering to the left and there's an ideological purge going on. But I don't think there's a comprehensive official plan for it all.

KUHN: In the past five years, space for public expression has been tightening in media, in the arts and in civil society. And education has not been spared either. The effect of all this on international scholarship became clear last month when Chinese censors briefly succeeded in getting the Cambridge University Press to censor articles from an influential journal it puts out called The China Quarterly.

JEFFREY WASSERSTROM: It violated the integrity of the journal.

SHAPIRO: That's University of California, Irvine historian Jeff Wasserstrom. China recently tried to get another academic journal he edits to censor itself.

WASSERSTROM: There's a tendency to think that since Mao's death in 1976, that with some occasional slips back there's been at least a two-steps-forward, one-step-back pattern in a kind of lessening of controls on campuses.

KUHN: That's why the current ideological purge, Wasserstrom says, is a worrisome step backwards. Then again, Beijing Normal University's Shi Jiepeng consoles himself by taking an even longer view. During China's imperial dynasties, he says, intellectuals were often persecuted for what they wrote.

SHI: (Through interpreter) Back in those days, people's whole families were executed. Me, I only lost my job. So things are much better now.